Scientists identify mysterious particle that could be made of pure gluons
Researchers have determined the identity of an exotic particle called X(2370), finding it matches theoretical predictions for a "glueball"—matter composed entirely of gluons, the force-carrying particles that bind quarks together. The discovery, reported in Physical Review Letters, validates decades-old theories and could reshape understanding of fundamental particle physics and the composition of matter.
Originaltitel: Determination of Spin-Parity Quantum Numbers of <em>X</em>(2370) as 0<sup>-+</sup> from <em>J</em>/ψ → γ<em>K<sub>S</sub></em><sup>0</sup><em>K<sub>S</sub></em><sup>0</sup>η'
<p>Based on (10087 ± 44)x10<sup>6</sup> J/ψ events collected with the BESIII detector, a partial wave analysis of the decay J/ψ → γK<sub>S</sub><sup>0</sup>K<sub>S</sub><sup>0</sup>η' is performed. The mass and width of the X(2370) are measured to be 2395 ± 11(stat)<sub>-94</sub><sup>+26</sup>(syst) MeV/c<sup>2</sup> and 188<sub>-17</sub><sup>+18</sup>(stat)<sub>-33</sub><sup>+124</sup>(syst) MeV, respectively. The corresponding product branching fraction is B[J/ψ → γX(2370)] x B[X(2370) → f<sub>0</sub>(980)η'] x B[f<sub>0</sub>(980) → K<sub>S</sub><sup>0</sup>K<sub>S</sub><sup>0</sup>] = (1.31±0.22) (stat)<sub>-0.84</sub><sup>+2.85</sup> (syst)x10<sup>-5</sup>. The statistical significance of the X(2370) is greater than 11.7σ and the spin parity is determined to be 0<sup>-+</sup> for the first time. The measured mass and spin parity of the X(2370) are consistent with the predictions of the lightest pseudoscalar glueball.</p>